1. Field of the Invention
This invention relates to a bias magnetic field moving apparatus for a photomagnetic recording apparatus wherein a bias magnetic field applying member, applying a bias magnetic field to a photomagnetic recording medium, approaches or separates from the photomagnetic recording medium.
2. Related Art Statement
Recently, the development of the industry relating to information is remarkable and the amount of information to be handled tends to increase. Therefore, instead of the recording and reproducing apparatus recording and reproducing information by using the conventional magnetic head, an optical recording and reproducing apparatus using a light beam has come to be noted.
In such an optical recording and reproducing apparatus, a recording and reproducing apparatus of a photomagnetic systems (called a photomagnetic recording and reproducing apparatus hereinafter) wherein information can be erased and re-written is noted.
In such a photomagnetic recording and reproducing apparatus, a bias magnetic field must be applied to the recording medium at the time of erasing and recording information and therefore a magnetic field applying apparatus is provided. In this magnetic field applying apparatus, a magnetic field applying member using a permanent magnet or coil is arranged close to the recording medium at the time of erasing and recording information.
As shown, for example, in the publication of Japanese Patent Application Laid Open No. 157364/1987, in the above mentioned photomagnetic recording and reproducing apparatus, a disc-like recording medium (called also a disc) is contained generally within a cartridge and the above mentioned magnetic field applying member is put into an opening formed in the above mentioned cartridge to apply a magnetic field and is arranged close to the disc surface. In the case of fitting (loading) and removing (unloading) the above mentioned cartridge to and from the photomagnetic recording and reproducing apparatus, the above mentioned magnetic field applying member must be separated from the cartridge. Therefore, as shown, for example, in the publication of the above mentioned Japanese Patent Application Laid Open No. 157364/1987, a magnetic field applying member is fitted to the end of an arm rotated as operatively connected with the loading and unloading operation to form a bias magnetic field moving apparatus by which the magnetic field applying member is close to or separated from a cartridge.
However, in the conventional bias magnetic field moving apparatus, as the magnetic field applying member is fitted to the arm so as to be parallel with the cartridge and disc close to the cartridge, when separated from the cartridge, the above mentioned magnetic field applying member will be oblique to the cartridge. Therefore, there are problems that the magnetic field applying member moving range is large, that is, the magnetic field applying member upward projecting amount is large and the photomagnetic recording apparatus is large in the size.